Perrigo G, Belvin L, vom Saal F S
Division of Biological Sciences, University of Missouri-Columbia 65211.
Physiol Behav. 1991 Aug;50(2):287-96. doi: 10.1016/0031-9384(91)90068-y.
In male house mice (Mus domesticus and M. musculus), the act of coital ejaculation provides a fail-safe neural signal for timing the birth of their offspring. A unique aspect of this phenomenon is the extraordinary latency that can occur between the stimulus (ejaculation) and its adaptive neural response (male mice cease killing pups and behave parentally toward them). Thus the inhibition of infanticide is routinely time-delayed for many days after mating. In the absence of mating, cohabitation with a female will not inhibit infanticide in CF-1 stock males (M. domesticus), whereas the birth of pups in the male's home cage will inhibit infanticide. But with regard to the ejaculatory phenomenon, which also includes the spontaneous reemergence of infanticide 50-60 days after mating, this entire behavioral cycle toward pups can occur in the total absence of regular time cues from a light/dark cycle following ejaculation. However, exposure to photoperiodic (L:D 12:12) or constant light (LL) accelerated the transition time from infanticide to parenting after ejaculation, while in constant dark (DD), the transition time to parenting was significantly prolonged. The time interval between ejaculation and the inhibition of infanticide, which varied among individuals first mated at 6 months of age, was repeatable when the same males were remated at 9 months of age; however, when males were again mated at 18 months of age, the time interval between ejaculation and parenting was dramatically prolonged. In general, coital ejaculation triggers a neural timing system that cannot be explained by any presently known physiological mechanism. Our results do suggest, however, that the neural timing variation observed among individuals is influenced by sex steroid exposure during late fetal development.
在雄性家鼠（小家鼠和小鼠）中，性交射精行为为其后代出生时间提供了一种可靠的神经信号。这一现象的独特之处在于刺激（射精）与其适应性神经反应（雄性小鼠停止杀害幼崽并表现出亲代行为）之间可能出现的超长延迟。因此，杀婴行为的抑制通常在交配后会延迟许多天。在没有交配的情况下，与雌性同居不会抑制CF - 1品系雄性小家鼠的杀婴行为，而在雄性的饲养笼中产仔则会抑制杀婴行为。但是关于射精现象，其中还包括交配后50 - 60天杀婴行为的自发再次出现，在射精后完全没有来自光/暗周期的常规时间线索的情况下，这种针对幼崽的整个行为周期都可能发生。然而，暴露于光周期（L:D 12:12）或持续光照（LL）会加速射精后从杀婴行为向亲代行为的转变时间，而在持续黑暗（DD）条件下，向亲代行为的转变时间则会显著延长。在6个月龄首次交配的个体中，射精与杀婴行为抑制之间的时间间隔因人而异，当相同雄性在9个月龄再次交配时，该时间间隔是可重复的；然而，当雄性在18个月龄再次交配时，射精与亲代行为之间的时间间隔会显著延长。一般来说，性交射精触发了一个神经计时系统，目前已知的任何生理机制都无法解释这一系统。不过，我们的结果确实表明，个体间观察到的神经计时差异受到胎儿后期发育期间性类固醇暴露的影响。
